699 - The Falling Leaves

感觉这个题目就是在考察非递归先序建树，首先将所有的数据全部读入进来，然后利用栈非递归建树。将根节点所在的标志记为0，如果同时如果从当前节点向左，则相应的标志减一，如果是向右，则相应的标志加一，同时建立相应的标志到该标志的“总数”的映射，最后输出即可。对每个节点，设置一个pos，来记录相应的标志，具体的实现见源代码：

#include<iostream>#include<vector>#include<string>#include<set>#include<stack>#include<queue>#include<map>#include<algorithm>#include<cmath>#include<iomanip>#include<sstream>using namespace std;typedef struct node{int val;struct node* left, *right;int pos;node(int value){val = value; left = NULL;right = NULL;}}node;int main(){string s;map<int, int> in2in;int Case = 0;stack<node*> st;int pos;vector<int> data;while (getline(cin, s)){if (s == "-1") break;stringstream ss(s);int t;while (ss >> t){data.push_back(t);}}int position = 0;while (position < data.size()){pos = 0;node* root = new node(data[position]);root->pos = 0;st.push(root);in2in[pos] = data[position];position++;int length = data.size();while (position < length && !st.empty()){node *temp = st.top();pos = temp->pos;while (data[position] != -1){temp->left = new node(data[position]);temp = temp->left;pos--;temp->pos = pos;if (in2in.find(pos) == in2in.end()) in2in[pos] = data[position];else in2in[pos] += data[position];position++;st.push(temp);}position++;while (position < length&&data[position] == -1){st.pop();if (st.empty()) break;temp = st.top();position++;pos = temp->pos;}if (position < length&&data[position] != -1){st.pop();temp->right = new node(data[position]);temp = temp->right;pos++;temp->pos = pos;if (in2in.find(pos) == in2in.end()) in2in[pos] = data[position];else in2in[pos] += data[position];st.push(temp);position++;}}Case++;cout << "Case " << Case << ":" << endl;for (auto it = in2in.begin(); it != in2in.end();){cout << it->second;it++;if (it != in2in.end()) cout << " ";}cout << endl << endl;in2in.clear();position++;}//system("pause");return 0;}